The invention relates to a packing element comprising preferably one cylindrical outer cover and having at least one guiding surface arranged in the interior thereof.
Packing elements of the type addressed here are applied mainly where an interchange of substances between gas streams and liquid is desired, for example absorption, desorption, destillation, rectification, extraction, humidification, condensation, and the like. This type of packing element has proven to be especially successful in the field of waste water technology. Here it is employed both in random dumping and in ordered patterned rows and, as is the case particularly with biological waste gas treatment, serve as growing surfaces for "biofilm".
Numerous variations of this type of packing element are known. These are usually comprised of a cylindrical outer cover, either having openings in the cover surface or having a web structure. Inside such outer covers there are inserts having at least one guiding surface for increasing the specific surface of the packing element. The guiding surface or guiding surfaces inside of the packing element thus form drain surfaces and/or growing surfaces for the "biofilm".
The guiding surface or guiding surfaces unavoidably restrict the hydraulic properties of the packing element, i.e. the dumping or grouping of the packing elements resulting therefrom. This in turn increases the energy expenditure for passing the available medium through the packing element. The problem then is to so construct the packing element, particularly the guiding surfaces arranged therein such that these constitute a successful compromise between a good passage of gases and/or passage of liquids on the one hand and a satisfactory interchange of substances on the other hand. Moreover, the packing elements must have a sufficient inherent stability so as not to become deformed under the dead weight of other packing elements and/or the hydraulic stresses when large quantities of packing elements are dumped or packed. Finally, a good sludge discharge, especially of dead biomass, must be ensured for reliable prevention of blockages in the packing elements.